A major challenge in cell and organism biology is to understand how living cell physiology[unreadable] emerges from the biophysical properties of individual macromolecules. The morphological and[unreadable] physical behaviors of cells required for cell adhesion, migration and division depend on the proper[unreadable] spatial and temporal regulation of a vast hierarchy of multi-protein machines, called the cytoskeleton.[unreadable] However, while we are gaining increasing amounts of knowledge of properties of individual[unreadable] cytoskeletal proteins, we have very little knowledge about the self-assembly and physical properties of[unreadable] multi-protein assemblies that form physical structures to transmit mechanical information up to cellular[unreadable] length scales. For example, we do not understand how forces generated by individual molecular[unreadable] motors are exploited by cytoskeletal assemblies to regulate morphogenesis and force generation at[unreadable] the cellular level. Current understanding of the physical behavior of the cellular cytoskeleton has[unreadable] been limited both by the lack of experimental techniques to probe the dynamic structure and physical[unreadable] properties of mesoscopic cytoskeletal assemblies in living cells. I propose to establish the[unreadable] experimental tools to study the biophysical properties of cytoskeletal matter in living cells by[unreadable] integrating approaches from condensed matter physics with molecular cell biology. This work will[unreadable] identify the underlying physics of emergent cytoskeletal assemblies and will provide predictive[unreadable] analytical models to link our understanding of the biophysics of molecules to cell behaviors. Finally,[unreadable] this work will impact the treatment of diseases that are a result of misregulation of the physical[unreadable] behaviors of cells, including cancer metastasis and cardiac diseases.[unreadable]